1. Field of the Invention
Embodiments disclosed herein generally relate to the data storage field, and more particularly, relate to a method, apparatus, and system for implementing enhanced electric damage prevention of spin-torque oscillator (STO) for hard disk drives (HDDs) using microwave assisted magnetic recording (MAMR) technology.
2. Description of the Related Art
In a HDD or a disk-drive system or magnetic recording system, read and write elements are located in a head slider of a magnetic head, which flies over a recording media or a disk surface. The fly-height of the slider-to-disk has become smaller as storage densities continue to increase. In recent years, MAMR technology has been developed in order to increase the recording density of a HDD. MAMR technology performs magnetic recording using a microwave assisted effect generated by a STO incorporated in the head slider.
The STO is connected to two electrodes in the head slider, which are a lower potential side electrode and a higher potential side electrode. Both electrodes are formed near the surface of the head slider, facing a disk. The STO is biased by a preamplifier (preamp), which is located in the HDD. The preamp controls the potential of the electrodes, and allows current to flow through the STO.
However, when the head slider contacts the disk or magnetic recording medium while current is flowing through the STO, breakdown of the STO can be caused. The breakdown of the STO is a large issue for HDD using MAMR technology. After repeated use, the breakdown process of the STO typically happens in the following manner: first, the lower potential side electrode, which is the lowest point of the head slider, contacts the disk. A large amount of current then flows from the higher potential side electrode, through the STO to the lower potential side electrode, and finally to the disk. The STO is broken by the large amount of current that consistently flows through the system.
Therefore, there is a need in the art for a MAMR head structure and a preamp circuit with electric damage protection to prevent breakdown of the STO.